Fix misuses of bdevname()

bdevname() fills the buffer that it is given as a parameter, so calling
strcpy() or snprintf() on the returned value is redundant (and probably not
guaranteed to work - I don't think strcpy and snprintf support overlapping
buffers.)
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

block/blktrace.c

@@ -476,7 +476,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 
 	switch (cmd) {
 	case BLKTRACESETUP:
-		strcpy(b, bdevname(bdev, b));
+		bdevname(bdev, b);
 		ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
 		break;
 	case BLKTRACESTART:

block/compat_ioctl.c

@@ -555,7 +555,7 @@ static int compat_blk_trace_setup(struct block_device *bdev, char __user *arg)
 	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
 		return -EFAULT;
 
-	strcpy(b, bdevname(bdev, b));
+	bdevname(bdev, b);
 
 	buts = (struct blk_user_trace_setup) {
 		.act_mask = cbuts.act_mask,

fs/ext4/mballoc.c

@@ -2639,8 +2639,7 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
 	struct proc_dir_entry *proc;
 	char devname[64];
 
-	snprintf(devname, sizeof(devname) - 1, "%s",
-		bdevname(sb->s_bdev, devname));
+	bdevname(sb->s_bdev, devname);
 	sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4);
 
 	MB_PROC_HANDLER(EXT4_MB_STATS_NAME, stats);
@@ -2674,8 +2673,7 @@ static int ext4_mb_destroy_per_dev_proc(struct super_block *sb)
 	if (sbi->s_mb_proc == NULL)
 		return -EINVAL;
 
-	snprintf(devname, sizeof(devname) - 1, "%s",
-		bdevname(sb->s_bdev, devname));
+	bdevname(sb->s_bdev, devname);
 	remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_mb_proc);
 	remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_mb_proc);
 	remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_mb_proc);

fs/jbd2/journal.c

@@ -901,7 +901,7 @@ static void jbd2_stats_proc_init(journal_t *journal)
 {
 	char name[BDEVNAME_SIZE];
 
-	snprintf(name, sizeof(name) - 1, "%s", bdevname(journal->j_dev, name));
+	bdevname(journal->j_dev, name);
 	journal->j_proc_entry = proc_mkdir(name, proc_jbd2_stats);
 	if (journal->j_proc_entry) {
 		proc_create_data("history", S_IRUGO, journal->j_proc_entry,
@@ -915,7 +915,7 @@ static void jbd2_stats_proc_exit(journal_t *journal)
 {
 	char name[BDEVNAME_SIZE];
 
-	snprintf(name, sizeof(name) - 1, "%s", bdevname(journal->j_dev, name));
+	bdevname(journal->j_dev, name);
 	remove_proc_entry("info", journal->j_proc_entry);
 	remove_proc_entry("history", journal->j_proc_entry);
 	remove_proc_entry(name, proc_jbd2_stats);